The invention relates to a wheel nut having a nut body with a widened radial collar and with a thrust washer which is held rotatably and captively on the nut body by a locking means, and having a cap arranged on the nut body. The invention relates, furthermore, to a fastening element of this type.
Wheel nuts or fastening elements of this type, such as, for example, wheel screws with a decorative cap, are known in the field of motor vehicle technology. They serve, in particular, for the fastening of wheel rims, and above all of high-quality aluminum rims, but also steel rims, on a wheel hub. The caps are produced from highly polished stainless steel and are placed onto the engagement part of a nut or of a fastening element, said engagement part being in most cases of hexagonal design.
It is customary to connect such a cap firmly to the fastening element or to the nut body of a wheel nut by means of electrical ring welding. It is also customary for the cap to be fastened on the nut body by adhesive bonding.
When the cap is being welded to the fastening element or to the nut body of the wheel nut, on the one hand, a complicated welding appliance is required. On the other hand, damage to the visible surface of the cap may occur. The highly polished surface of the cap can be dulled by an electrode being applied. The bearing surface of the nut body or of the fastening element, said bearing surface being in engagement with the surface of a thrust washer, may also be damaged. This damage arises due to the fact that the electrodes necessary for the welding operation are applied at these points. Furthermore, satisfactory welding between the cap and the nut body or fastening element is possible only when the surfaces of the individual components are electrically conductive. This means that, for welding purposes, the surface of the components must, for example, be galvanized.
Since then, however, other surface coatings, such as the application of a lacquer layer in the form of a zinc lamellar coating, have also been employed, but these are, in part, not electrically conductive and therefore rule out a welded connection.